We propose to organize a cooperative group of institutions and individuals that will comprise the American College of Radiology Oncologic Imaging Network (ACROIN). ACROIN will develop clinical trials through its committee structure and the recruitment of ad hoc participants to rigorously assess both emerging and more stable imaging technologies as they relate to patients with cancer. Ultimately, ACROIN's goals are to: increase patient survival; improve quality of life through reduced invasiveness of diagnosis and treatment; improve patients' sense of well-being through greater rapidity and certainty of diagnosis and treatment; reduce diagnostic and therapeutic morbidity; hasten the translation of discovery to clinical technology; and speed the diffusion of worthwhile technologies into clinical practice. ACROIN will accomplish these goals by several strategies, including: a focus on the most important malignancies and technologies; an appropriate mix of trials between emerging and mature technologies; evaluation using a variety of endpoints -from tests of simple accuracy to assessment of patient outcomes and cost-effectiveness, according to the maturity of the technology; flexible, broad-based collaboration between core and ad hoc participants, including institutions, scientists, industry, payors, and patients; establishment of an organization designed to speed the development and implementation of trials and hasten dissemination of their findings; and reliance on the extensive past experience of the Headquarters and Biostatistical Center in conducting high quality clinical trials. ACROIN has developed an extensive committee structure to fulfill its functions; secured the commitment of 42 leading departments of radiology that they will try to qualify as core institutional participants; received letters of collaboration from eight other cooperative groups - each of which has designated a representative to ACROIN; and received the promises of a number of commercial companies and insurers that they will participate in and support ACROIN once it is established.